This study randomized 302 men between 48-82 years who had 10-core biopsy proven low volume Gleason 5-6 prostate cancer and who were on an active surveillance program, to receive dutasteride 0.5 mg daily for 3 years or placebo. The men had to have cT1 – cT2a disease and PSA <11ng/mL, 4 cores, > 50% of any core, Gleason score 4), and also therapeutic progression was recorded, being either surgery, radiotherapy or hormonal therapy. The findings were that dutasteride reduced pathological and therapeutic progression albeit not reaching statistical significance. This meant that for men on active surveillance there was a delay to needing further intervention. Men receiving dutasteride were also less anxious, and had improvement in urinary symptoms from a large prostate. Dutasteride is useful in men on an active surveillance program especially if they have a large prostate.